The Overview to our Center application elucidates our vision of how and why late life depression prevention effectiveness research must be advanced in the next five years. The Research Methods Core (RMC) will provide the infrastructure to support the development of innovative methodologies to address the research issues and goals that emerge from this vision. Thus, the RMC will forge methodologic bridges between the Center's overall vision, on the one hand, and the research to be accomplished in order to meet it. An equally important RMC goal is to contribute to progress of the science of prevention researchat both the level of effectiveness assessment and the level of sustainability and transferwithin the mental health and aging research and practice communities. The RMC will accomplish these objectives through the efforts of a unified, multidisciplinary team of methodologists. This team will be organized into three subgroups (Units) with expertise brought to bear on specific methodologic areas: 1. The Assessment of Risk and Intervention Outcomes Unit will focus on the development and application of a new generation of electronic assessment strategies for measuring both risk factors and intervention outcomes in depression prevention trials. Domains of focus include the measurement of depressive symptoms and symptoms of other comorbidities; cognitive status; and overall functional status and disability. 2. The Research Design and Biostatistics Unit will focus on the development and application of models to characterize dynamic patterns of risk factors and transition between states/levels of depression, as well as on the development of methods to promote the efficient analysis of data from response-adaptive allocation research designs. 3. The Implementation. Portabilitv. Sustainabilitv and Migration Unit will focus on the application of tools to promote intervention dissemination and sustainability, with an emphasis on the use of methods that better characterize the content and delivery of interventions, as well as determine interventions' economic feasibility. Moreover, this Unit will work on the development and initial testing of strategies to migrate traditional interventions to electronic delivery modes. Within each RMC Unit, work will be pursued at two levels of function: (a) direct research investigation of new tools and approaches, utilizing the Principal Research Core projects as critical platforms for this work and (b) dissemination and training efforts both within and beyond the Center, involving close liaisons with the Operations Core so that new RMC tools and approaches can be smoothly transferred to the Operations Core 'loolbox of Center resources and strategies.